Optical bar code readers read data represented by bar code symbols. A bar code symbol is an array of rectangular bars and spaces that are arranged in a specific way to represent elements of data in machine readable form. Optical bar code readers typically transmit light onto a symbol and receive light reflected off of the symbol. The received light is interpreted to extract the data represented by the symbol.
One dimensional (1D) optical bar code readers are characterized by reading data that is encoded along a single axis, in the widths of bars and spaces, so that such symbols may be read from a single scan along that axis, provided that the symbol is imaged with a sufficiently high resolution along that axis.
In order to allow the encoding of larger amounts of data in a single bar code symbol, a number of 1D stacked bar code symbologies have been developed which partition encoded data into multiple rows, each including a respective 1D bar code pattern, all or most all of which must be scanned and decoded, then linked together to form a complete message. scanning still requires relatively high resolution in one dimension only, but multiple linear scans, or two dimensional scans, are needed to read the whole symbol.
A class of bar code symbologies known as two dimensional (2D) matrix symbologies have been developed which offer greater data densities and capacities than 1D symbologies. 2D matrix codes encode data as dark or light data elements within a regular polygonal matrix, generally accompanied by graphical finder, orientation, and/or reference structures.
Bar codes are widely used to encode information about goods and services. They are used, either directly or with associated packaging, on an enormous range of goods and products. These include consumer goods such as food and beverage items, personal care products, clothing and apparel, home furnishings, linens, kitchenware, pharmaceuticals, hardware, electronics, appliances, sports and exercise equipment, toys and games, and reading materials. Manufacturing and industrial goods and equipment, including raw (such as felled timber) and finished goods, are also commonly marked directly with, or associated to, bar codes. The codes may contain information including the description of the item, pricing, size, weight, source or manufacturer in short, any desired information that may be captured within the data capacity constraints of the particular bar code symbology being used.
The usefulness of bar codes is not limited to goods and products, but extends to services. Vehicle rental and transportation for hire, such as car rental or leasing and travel by airplane, train, ship, subway, and bus may all be effected through transactions that include the use of bar codes, as may reservation and use of hotel facilities; use of mail, courier, and other package delivery services; rental of lockers and other storage facilities; and event ticketing, such as for movies, concerts, lectures or speeches, plays, seminars, and trade shows. It is, in fact, reasonable to say that any transaction involving an exchange of money for goods or services may be facilitated by use of bar codes, and that many, if not most, such transactions are so facilitated.
Historically the most common use for bar codes in consumer transactions is simply to correlate the item being purchased with its current price, but the potential uses are much broader. When a bar code is scanned at, for example, the checkout counter of a retail store, a simple and direct use of the information in the bar code is to query a store lookup database to retrieve the current pricing of the product in question. A second layer of usefulness may be added by using the bar code information to track store inventory. A third layer might involve using the information for promotional programs, such as triggering printout of coupons based on the items being purchased. If the transaction is of the type where the customer has electronically identified him or herself to the sore, as by using a customer identification card or store issued credit or debit card, the store might also link the items being purchased to the customer's record, and this information could be used for rebates, buying incentive programs, or mailing of targeted promotional materials to the customer, for example.
Until recently, use of bar codes has been largely limited to the vendor. First, there have been few products available to the customer or consumer for capturing and using bar code information. Portable, handheld electronic devices for consumers have been present for many years, such as Personal Digital Assistants (PDAs) and cellular telephones. However, bar code scanning capability has been provided only in dedicated devices that were not aimed at the consumer market, and which generally would have presented a very unfavorable cost/benefit profile for that market. These dedicated scanners are generally quite expensive, and there has simply been no application for their use that would benefit a consumer proportionately to their cost.